Ion analysis devices such as mass spectrometers have been used to great effect to analyze and characterize samples both simple and complex. Such devices require samples to be ionized so that mass to charge ratio (m/z) may be measured by various methods of manipulation of the ions. Early ion sources involved such methods as the bombarding of samples with electrons. These methods, however, often caused ions to be produced with very high energy, which left them liable to fragment. Later, so called “soft” ionization techniques, notably electrospray, atmospheric pressure chemical ionization (APCI) and matrix assisted laser desorption ionization (MALDI), were developed, each of which enabled sample ion fragmentation to be better controlled, and for sample ions to be detected in their entirety.
The analysis of solid samples and surfaces with on analysis devices has always provided particular challenges, as traditional soft ionization techniques are appropriate only to the analysis of liquid samples or samples held in solution. Certain industries however, such as food, homeland security, and forensics, would find great benefit in a source able to effectively produce molecular or pseudo molecular ions from a solid sample without significant damage to the surface.